Downhole devices, associated apparatus and methods

Abstract

There are described downhole devices, methods and other apparatus, which may be used to generate energy, monitor fluids and/or provide control signals or otherwise trigger for actuation. The devices, methods, etc. may provide improved autonomy and/or accuracy, while at the same time minimise any effect on the operation of a well. Such devices and methods may be particularly useful downhole and in remote locations. An example of a device comprises a generating material having a fluid contact surface, that contact surface being configured to be in contact with a fluid downhole. The generating material may be configured to generate an electric charge at the material in response a fluid at the contact surface. In some examples, the device further comprises a signal source configured to provide a signal in response to a generated electric charge at the generating material.

The invention claimed is: 
     
       1. A downhole device comprising:
 a generating material having a fluid contact surface, that contact surface being configured to be in contact with a fluid downhole, and the generating material being configured to generate an electric charge at the generating material in response a fluid at the contact surface; the device further comprising 
 a signal source configured to provide a signal in response to a generated electric charge at the generating material; 
 a flow control mechanism in communication with the signal source, the flow control mechanism being configured to operate responsive to signals being provided from the signal source and in response to the generated electric charge at the generating material, wherein the flow control mechanism comprises an activation device, the activation device comprising, 
 a retainer configured to retain the flow control mechanism in a particular configuration, and to activate upon receipt of a signal from the signal source so as to release the flow control mechanism, wherein the retainer comprises a conducting sacrificial element configured such that current from the signal passes through the conducting sacrificial element, and further configured such that when a rate of charge flowing through the conducting sacrificial element exceeds a particular threshold, a structural integrity of the conducting sacrificial element decreases to allow activation of the flow control mechanism; and, 
 a biasing mechanism configured to assist with operable opening/closing of the flow control mechanism. 
 
     
     
       2. The device according to  claim 1 , wherein the generating material is configured to generate at least a triboelectric charge in response a fluid flowing at the contact surface. 
     
     
       3. The device according to  claim 1 , wherein the signal source is configured to provide a fluid monitoring signal in response to the generated electric charge at the generating material. 
     
     
       4. The device according to  claim 3 , wherein the device is configured to monitor for an expected fluid property. 
     
     
       5. The device according to  claim 3 , wherein the device is configured to monitor for a presence of a constituent fluid of a fluid at the contact surface. 
     
     
       6. The device according to  claim 5 , wherein the device is configured to monitor water composition of fluid at the contact surface. 
     
     
       7. The device according to  claim 1 , wherein the generating material comprises defined flow paths along which fluid can flow and be in contact with the contact surface. 
     
     
       8. The device according to  claim 7 , wherein the flow paths comprise channels formed through the generating material, and through which fluid can flow, the formed channels being defined by regular and/or irregular structures in the generating material. 
     
     
       9. The device according to  claim 8 , wherein the channels comprise nanotubes. 
     
     
       10. The device according to  claim 1 , wherein the signal source is configured such that the signal is provided directly from the electric charge generated as a result of fluid at the contact surface. 
     
     
       11. The device according to  claim 10 , wherein the signal source is configured to provide a current signal from the electric charge generated at the generating material, or a charge potential signal relating to the electric charge at the generating material. 
     
     
       12. The device according to  claim 1 , wherein the device comprises a processor module, the processor module being configured to receive or measure electric charge being generated in the material and to provide signal to the signal source for further communication. 
     
     
       13. The device according to  claim 1 , wherein the signal source is configured to provide a power signal in response to electric charge being generated at the generating material, that power signal being usable to provide power to a further downhole device and/or a power supply. 
     
     
       14. The device according to  claim 11 , wherein the device is configured such that the threshold relates to the electric charge expected from a particular fluid property to be monitored. 
     
     
       15. The device according to  claim 2 , wherein the particular monitored fluid property comprises water cut. 
     
     
       16. The device according to  claim 1 , wherein the flow control mechanism is configured as an inflow control device together with wellbore completion. 
     
     
       17. The device according to  claim 16 , wherein the device comprises a filter provided upstream of the generating material. 
     
     
       18. A downhole method comprising:
 providing fluid at a contact surface of a generating material so as to generate an electric charge in response that fluid; 
 providing a signal downhole in response to a generated electric charge at the generating material; 
 providing a flow control mechanism downhole to receive the signal, the flow control mechanism being configured to operate responsive to the signal provided in response to the generated electric chare at the generating material; 
 retaining the flow control mechanism in a particular configuration via an activation device, wherein the activation device comprises a retainer, the retainer being a conducting sacrificial element; 
 activating the activation device upon receipt of the signal; 
 passing a current though the conducting sacrificial element upon receipt of the signal, wherein the conducting sacrificial element is configured such that when a rate of charge flowing through the element exceeds a particular threshold, a structural integrity of the conducting sacrificial element decreases to allow activation of the flow control mechanism; and, 
 assisting opening/closing of the flow control mechanism via a biasing mechanism. 
 
     
     
       19. The method according  claim 18 , wherein the generating material is configured to generate at least a triboelectric charge in response a fluid flowing at the contact surface.